Note: This species consists of approximately ten races or subspecies, all of which vary slightly in appearance.
This widespread species ranges from Alaska through most of Canada to Nova Scotia; through the western third of the U.S.; through the northern U.S. and a portion of the southeastern U.S. It occurs through most of Idaho.
It can be found in a variety of habitats, including meadows, fields, open woodlands, coastal dunes, and along streams.
Caterpillars feed on new leaves, flowers, and fruits of legumes, such as milk
vetches (Astragalus spp.), other vetches (Vicia spp.), peas (Lathyrus
spp.), lupines (Lupinus spp.), and deer weed (Lotus scoparius).
Adult: Butterflies drink flower nectar
The caterpillar is equipped with a honey gland, also known as a dorsal nectary organ, which emits a sugary solution agreeable to ants. The ants feed on the solution and in turn protect the caterpillar from predators. Also for protection, the caterpillar bears a pair of everscible tubercles or tentacles on the eighth segment. These tubercles are usually housed within the body, but when the caterpillar feels threatened by the approach of a potential predator, they can be pushed out to release a chemical which mimics an ant alarm pheromone. This scent causes the ants to become frenzied and aggressive, and the potential predator takes leave or is eaten by the ants. There is only one new generation of caterpillars each growing season. Each caterpillar undergoes four stages of growth, called instars. Pupae overwinter in a physiological state called diapause. Adults generally fly from April to June, but may be seen as early as February and as late as August in some locations. The butterflies are one of the first species typically seen in the spring.
Males actively patrol in search of receptive females. Females lay eggs singly on the flower buds or new leaves of host plants.
|Idaho Status:||Unprotected nongame species.|
|Global Rank:||G5; most populations are widespread, abundant, and secure. One subspecies in California, once thought to be extinct, is ranked T1, which means it is critically imperiled because of extreme rarity and is imminently vulnerable to extinction.|
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